A Wireless Local-Area Network (WLAN) typically comprises one or more Access Points (APs) that communicate with stations (STAs). WLAN communication protocols are specified, for example, in the IEEE 802.11 family of standards, such as in the 802.11n-2009 standard entitled “IEEE Standard for Information technology—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 5: Enhancements for Higher Throughput,” 2009; and in the 802.11ac-2013 standard entitled “IEEE Standard for Information technology—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 4: Enhancements for Very High Throughput for Operation in Bands below 6 GHz,” 2013, which are both incorporated herein by reference. WLANs are also commonly referred to as Wi-Fi networks.
A WLAN AP typically employs a certain scheduling scheme for scheduling transmissions of different STAs. For example, the Wi-Fi Alliance™ promotes a scheduling scheme called Wi-Fi Multi-Media (WMM®). Quality-of-Service (QoS) scheduling for WLAN is described, for example, in IEEE document P802.11e/D13.0 entitled “Amendment: Medium Access Control (MAC) Quality of Service (QoS) Enhancements,” January, 2005, which is incorporated herein by reference.